Keepers said the unidentified woman saw that Dorothy's water had broken Dec. 21 after a 16-month gestation. The tip allowed staff to be there to witness the rare event.

"We don't know who this woman was, but we are grateful to her. The webcam was like an extra pair of eyes," park manager Gary Gilmour said.

The female calf -- called Ailsa after the park's only female keeper -- was introduced to the media Thursday weighing 330 pounds at the age of 5 weeks. She was expected to grow to about 3,520 pounds, like her mother.

Ailsa was one of eight southern white rhinoceros -- which are actually gray -- born in captivity in Europe last year. About 11,000 of the endangered animals roam across southern Africa, according to the International Union for the Conservation of Nature.

The park set up the webcam because staff feared they would miss the birth, which for rhinos usually happen in the early morning. Staff have now installed a second outdoor webcam to allow viewers to watch Ailsa explore her new home.

-- Associated Press

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